I pried my pallets apart, for the most part. Some pallets are near impossible to pry apart though, and then you have to use the cut apart method. The sawzall (recipricating saw) works great for this. Usually you can get away with cutting one end with the saw and then pry apart the middle and other end. I think butt jointing the pallet boards would work too, as long as you lay the joint down on an upright piece (stud). I don't remember exactly how long it took me to take them apart, because it was a while back. I also did the work in little snippets of time, like one or two hours before work, or after work. (guessing, but maybe 30-45 minutes per pallet).
As far as winters here in Memphis, TN? Fairly mild...average temps in the 30's, dipping into the teens is a real cold snap for us and infrequent. I don't keep food and water in the coop night or day, and that seems to be different than what i see folks here on BYC doing. I have a different idea on that subject, though. Since my chickens free range in the fenced in yard (truly my actual BACKYARD, lol) all day, I don't want to encourage activity in the coop (except for laying and roosting). They roost at dusk and they go in as they please (door open) and when they are all in I shut them in. In the morning I let them out at sunrise more or less, every morning. I've found that feeding and watering them outside the coop cuts down on the mess INSIDE the coop. The recommended space allowance is 4 sq/ft per bird for the coop and 16 for the run. I have roughly half that amount of space in the coop, yet they all fit on the roosts and are not crowded at all. Just remember when you are getting advice by reading posts on BYC, that what works in New Mexico is not necessarily going to work as well in Canada or vice versa....consider your geographical area when making decisions. But since you are thinking that some time may be spent in the coop, I would use the 4 sq foot per bird minimum rule. Since you will have five birds, 20 sq feet would be minimum and my size coop would be perfect for you at 24 sq feet.